In general, a building having a plurality of floors, e.g. an apartment house and a skyscraper, uses flooring such as a soundproof material, a vibrationproof material, or a buffer material to block or suppress noise between floors.
For example, a glass wood insulator, an urethane foam board, expanded polystyrene foam (Styrofoam), a rock wood board, an expanded polyethylene insulating material, and a carbonized cork board are mainly used to realize a sound absorption and insulation effect of the building. Also, conventionally, a lightweight aerated concrete layer or an expanded polystyrene foam layer are used as a buffer layer to reduce inter-floor floor impact sound or enhance insulation of the apartment house or the skyscraper. However, this is not effective for sound absorption of the inter-floor floor impact sound. Accordingly, in recent years, a vibrationproof rubber pad is installed below the lightweight aerated concrete layer, or a technique for providing an air layer is suggested and realized.
However, although the rubber pad is inserted to absorb impact generated from an upper floor and vibration transmitted to a lower floor is slightly reduced in virtue of the elasticity of the rubber pad, all layers including a concrete slab layer, the rubber pad, the lightweight aerated concrete layer, and a floor finishing mortar layer are attached to each other, and thus a vibrationproof effect for the impact is reduced. Also, although the air layer is provided below the lightweight aerated concrete layer to realize a floating layer structure and reduce the inter-floor noise, the structure is complex due to its complex cross-section configuration, constructability is downgraded, and costs increase due to additional high priced material.